How to fade object alpha up/down with shader graph ?

Getting Started
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1

Hello, I know how to fade the alpha with a noise, but I would like to control the fade direction and for example start from the bottom to the top.

To illustrate here is the Brackeys video about it.

2

Bump.

Here is a more concrete example: https://www.ronja-tutorials.com/assets/images/posts/021/Result.gif

But instead of clipping I want to have a reduced alpha.